Dividing tens and hundreds

In your book, Maths Mela (Chapter 9), we ask: how many 3s are there in 150? Think of multiplication: ___ × 3 = 150. We know 5 × 3 = 15, so 50 × 3 = 150. That means 150 ÷ 3 = 50.

A known fact helps with bigger numbers. 4 ÷ 4 = 1, so 40 ÷ 4 = 10 and 400 ÷ 4 = 100. Look at dividing by 10: 40 ÷ 10 = 4, 400 ÷ 10 = 40 and 4000 ÷ 10 = 400. Each time the dividend has one more 0, the quotient has one more 0 too. In the place value chart, dividing by 10 moves every digit one place to the right.

Sometimes the dividend and the divisor both have extra 0s. 3300 ÷ 300: we know 33 ÷ 3 = 11, and 300 × 11 = 3300, so 3300 ÷ 300 = 11. In the same way, 2000 ÷ 20 = 100, because 20 × 100 = 2000. Always check with multiplication.

Sabina cycles 160 km in 20 days, the same distance each day. 160 ÷ 20: since 16 ÷ 2 = 8, and 20 × 8 = 160, she cycles 8 km a day. Seema pays ₹4200 in ₹100 notes: 4200 ÷ 100 = 42 notes.

We can also find a missing number. ___ ÷ 100 = 72: the missing dividend is 72 × 100 = 7200. 870 ÷ ___ = 87: what times 87 makes 870? 87 × 10 = 870, so the missing divisor is 10.